function  OnCollisionEnter  (collisionInfo : Collision) {
 if (collisionInfo.gameObject.tag == "Ship"){
 	//decide how we want to respond --> I decided to add forces, but you could do almost anything
  	var randy: int = Random.Range(-200, 200);
  	collisionInfo.gameObject.rigidbody.AddForce(Vector3.up * 500);
  	collisionInfo.gameObject.rigidbody.AddForce(Vector3.right * randy);
 }
} 